JSON DeserializeObject не удалось привести или преобразовать из System.String в модель

Я пытаюсь десериализовать JSON, вырежьте его, продолжайте показывать мне это исключение:

Could not cast or convert from System.String to SmartBookLibrary.ViewModel.BookJ1.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: Could not cast or convert from System.String to SmartBookLibrary.ViewModel.BookJ1.

Вот пример моего JSON:

{
  "authorfamily1": "von Goethe",
  "authorname1": "Johann",
  "authorsurname1": "Wolfgang",
  "title": "Fausto I",
  "extension": "epub",
  "md5": "58cb1dd438bc6c6027fcda9e7729e5ee",
  "isbn": "",
  "descr": "",
  "cover": "1"
},
{
  "authorfamily1": "von Goethe 1",
  "authorname1": "Johann",
  "authorsurname1": "Wolfgang",
  "title": "Fausto I",
  "extension": "epub",
  "md5": "58cb1dd438bc6c6027fcda9e7729e5ee",
  "isbn": "",
  "descr": "",
  "cover": "1"
}

Вот код:

var json = System.IO.File.ReadAllText("/data1.json");           
var courses = JsonConvert.DeserializeObject<Dictionary<string, BookJ1>>(json);

Вот моя модель или виртуальная машина:

public class BookJ1
{
    public string title { get; set; }
    public string isbn { get; set; }
    public string extension { get; set; }
    public string authorfamily1 { get; set; }
    public string authorname1 { get; set; }
    public string md5 { get; set; }
    public int cover { get; set; }
    [AllowHtml]
    [Column(TypeName = "text")]
    public string descr { get; set; }
}